Grab



1 1923" D. J. BARNARD GRAB Filed July 24 1922 3 Sheets-Sheet 3 6 ll 7 I agi, Z l 10 a 33 I o g I o 2 a E 4k lNl/E/V TOR.

Dec, 18, 1923.

D. J. BARNARD GRAB Filed July 24 1922 5 Sheets-Sheet 2 Dec. 118,, was. 1,4775% D. J. BARNARD GRAB Filed July 24 1922 5 Sheets-Sheet 5 Fig.5.

INVENTOR Mjamasma/w Patented Dec. i8, 1235.

U5 -All carat,

DUDLEY JAMES BARNARID, OF EARRING, ENG-LAND.

GRAB.

Application filed July 24,

To all whom it may concern:

Be it known that I, DUDLEY JAMES BAR- NARD, a subject of the King of Great Britain and Ireland, residing at 8 Strathfield Gardens, Barking, in the county of Essex, England, engineer, have invented certain new and useful Improvements in and Relating to Grabs, of which the following is a specification.

This present invention relates to improvements in and relating to grabs of the type in which all movements of the grab are usu: ally effected by a single chain or rope and it has for its object the improvement in the general arrangement and construction of the operative parts of the grab and in the provision of means for preventing the opening of the grab should the load be removed from the hauling chain or rope while the grab is being transported from one point to another.

The novel features formin r the subject of this invention are particular y designed for use in connection with the type of grabs described inthe specifications to my prior Patents No. 1,218,921 and No. 1,353,651 and relate particularly to the mechanism employed for locking the bucket sections in the closed position, to mechanism for releasing said mechanism either when the grab is dumped or when in mid-air by a hand rope connected to said mechanism, to mechanism for preventing the opening of the bucket sections when the load is removed from the hauling chain, and to the arrangement of the sheaves according to the purchase power required.

The locking mechanism described in my aforesaid specifications comprised a gravity catch mounted on the power shaft arranged to engage with projections-mounted on the crossbeam, according to the present invention it is proposed to mount a pair of gravity catches on the cross-beam said catches being so shaped that their lower ends may be connected together, the arrangement being such that as one catch falls out of engagement with co-acting parts provided on the sheave block plates, the other catch is also moved out of engagement with its coacting part.

The gravity catch on one side is maintained in its operative or locked position by means of a locking latch or lever pivoted 1922. Serial No. 577,224.

tion by means of a sliding weight or party the movements of which are controlled by a weighted lever pivoted on the sheave block plate said lever being itself controlled by a Weight or spring the tension of which varies according to the position of theframework relatively to the top cross bars.

When a grab of the type herein described is used in conjunction with a transporter or like device it is necessary to provide means for preventing the opening of the bucket sections, as during the time that the grab is being transported from one point to another the load is temporarily removed from the hauling chain and such means consists in part of a device secured tothe head of the grab through which the hauling chain is adapted to pass, said device being adapted to engage with a carriage provided on the transporter or like device. The other part of the device consists of a vertically dis-' posed gravity catch pivoted on one of the top bar plates said catch being adapted to. engage with a toothed member provided on the sheave block plate on the same side. The lower end of the gravity catch is formed to adapt it to co-act with the locking latch so that when said latch falls or is pulled into its inoperative position the gravity catch is also forced out of engagement with its co-acting toothed member.

Certain other modifications in the construction and arrangement of the parts of the grab will be more fully described here. after with reference to the accompanying drawings, in which Fig. 1 is a side elevation of a grab with the buckets in closed position.

Fig. 2 is a front elevation thereof.

Fig. 3 is a side elevation with the buckets in open position and ready for the closing movement.

Figs. 4 and 5 are views in side and front elevation respectively on an enlarged scale illustrating details of the locking mechanism, and,

Fig. 6 is a side elevation of a modified form of locking mechanism.

In the drawings 1 and 2 are the bucket sections pivoted on independent pins 3 and 4 on a cross beam 5, 6 and 7 are the top cross bars and 8 the spreader arms, one being arranged at each corner of the bucket sections. The means for maintaining the normal balance of the operative parts of the grab are the same as described in the specification to my aforesaid Patent No. 1,353,651 and consist of two vertically disposed telescopic devices arranged one on each side of.

the sheave block, one member 9 of each device being carried by the top cross bars, the other member 10 of each device being carried by the cross beam 5, each of said members9 andlO pass through a pair of sleeves or thimbles 11, 12 carried by the sheave block plates 13 and 14 maintained in fixed relation with respect to each other by the spacing blocks 60.

The arrangement of the sheaves in the form of grab illustrated in Figs. 1, 2 and 3 is such that a six to one purchase is obtained. To obtain this result, two sheaves 15 and 16 are mounted on the top crossbars 6 and 7 and four sheaves17, 18, 19 and 20 are carried by the sheave block plates 13 and 14. The hauling chain 21 is arranged as follows :-The chain enters the grab through a thimble or like part 22 carried by the top cross bars 6 and 7 and passes down under the sheave 17 up over the sheave 15, down under the sheave 18 across under the sheave 19 upward over the sheave 16 down under the sheave 20 and up to a shackle 23 secured toa plate 24 carried by the top cross-bars.

The locking mechanism, more clearly shown on the enlarged views (Figs. 4 and 5) consists of two gravity catches 25, 26, pivotally mounted between the plates forming the cross-beam 5. The inner end of the catch 25 is provided with a pin 27 adapted to engage with a slot 28 provided in the inner end of the catch 26, the arrangement being such that as the upper end of the catch 25 drops outwardly out of engagement with its coacting part 29 provided on the plate 13 the catch 26 is compelled to drop outv wardly out of engagement with its co-a-ctingpart '30 on the plate 14. The gravity catches 25, 26 are moved into their. operative position by a part '59 secured to and between the plates 13 and 14 (Figures 4 and 5) or one of the spacing blocks'60 may be employed for thispurpose (Figure 6). For thepurpose of maintaining the catch 25 in its operative or locked position, a projection 31 is provided on the upper end of said catch 25, said projection being engaged by a locking latch or lever 32 pivoted at 33 on the 13 said rod being provided with a part 36.

adapted to: co-act with a projection 37 provided on the latch 32, the arrangementbeing such that when the parts are in the position shown in Fig. 11 the upper end of the rod 34 engages: with a part 38 secured to the plate24 and removes the part 36 out of engagement with the projection 37 so'as to leave the latch 32 free to fall out of engagement with the projection 31 on the gravity catch 25. When the parts are in the position shown in Fig. 3, the rod 34 is drawn up into engagement with the projection 37 by a spring 39 and serves to hold the locking, latch 32 in engagement with the projection 31 while the buckets are being drawn into the closed position.

A modified form of locking mechanism is shown in Fig. 6 according to which the gravity catch 25 ismaintained in engage ment with the part, 29 on the plate 13 by means of a weight 40. the movements 0 41 pivoted at 42 on the plate 13 said lever being itself controlled by a spring'43 rod 44 and part 45 co-acting with a stop 46 on the lever 41. V i i In operation the locking mechanism above described is similar to that previously deshown in Fig. 6. \When the. sheave block is drawnup to the top of the grab into the position shown in Fig.1, the rod 44 will be depressed by the stop 38 and the part 45 will be withdrawn from engagement with the projection 46, so that when the grab is dumped or the hand rope 47 is pulled, the lever 41 which bears against a stop 48 formed on the upper part of the weight 40, lifts the weight free from the projection on the gravity catch 25 and'permits same to fall outwardly and so allows the buckets to fall into open position.

When a grab of the type herein described 7 is used in conjunction with a transporter f which are controlled by a weighted lever acrea e trated in Figs. 4 and 5 are employed, such means comprising a part 49 adapted to be secured to the head of the garband a vertically disposed gravity catch 50 and a toothed member- 51. The part 49 replaces the thimble or like part 22, through which the hauling chain is adapted to pass and saidpar't is adapted to engage with a carriage provided on thetransporteror like device and carries the entire load during the period of transportation. Ihe gravity catch 50 is pivoted on one of the'top bar plates 24 and a projection52provided near the lower end-thereof is adapted'to engage with the toothed member 51 secured on the plate 13. Thelower end ofthe catch 50 is formed to adapt it to co-act with apart 53 formed on or secured to-the locking latch 32 so that when such latch falls due tothe dumping of the grab or is pulled into its inoperative position while in mid-air by the'cord 47 attached to its outer end the gravity catch 50 is also forced out of engagement with its co-acting toothed member 51. 7

While it is not considered necessary, a locking latch 32 and vertically disposed gravity catch 50 and co-acting toothed member maybe provided on each side of the grab, in which case suitable means would be provided for connecting the two locking latches 32 so as to enable same to work in unison.

The method of arranging the sheaves to obtain ,a four to one purchase is also diagrammatically illustrated in Figs. 4 and 5. In this case only three sheaves are employed, one 54 mounted between the top bar plates 24, the spindle 55 thereof being disposed at an angle sons to provide a straight lead for the chainor rope to pass on to the sheaves 56 and 57 carried by the plates 13 and 14. The hauling rope 21 passes through the part 49 centrally .down and under the sheave 56 up over the sheave 54 and down and under 'the'sheave 57 the free end being secured to -a fixed part of the grab at 58 or at any other convenient point.

If itis desired to employ the locking mechanism as described in'Fig. 6 witha grab provided With the gravity catch 50 and its co-acting parts, the upper end of the weight 40' may be provided with a cam shaped part adapted on being raised to throw the catch 50 outof engagement with the part 51.

I claim 7 1. In a [grab of the type provided with means connecting the cross-beam and movable sheave block, the combination of means comprising a pair of gravity catches pivoted on independent pivots on the crossbeam, means connecting the lower ends of said catches 'to cause'samato :operate in unison witheach other comprising ;a pin on the lower end ofone catch, aslot in the lower end of the other catch ,with which said pin engages, means on the sheave block plates for moving said catchesinto their operative position, means on'= the sheave block plates with which said catches engage, movable means mounted on said sheave block plate adapted to engagewith one of said catches, and spring controlled means mounted on one of said sheave block plates arranged to control the movements of said movable means according .to the relative positionoii the operative parts of the grab.

2. In a grab of the type provided with means connectingthe cross-beam and ,movable sheave block,the,-combination of means comprisi-nlg a pair of gravity catches pivoted on the cross-beam a projection on the upper end of one of said catches, means on the sheave block plates with which said catches engage, a bell crank lever pivoted on said sheave block plate adapted to ,en-

gage with said projection, and spring controlled means arrangedto control the movements of said bell crank lever according to the relative position of the operative parts of the grab.

3. In argrab of thetype provided with means connectingthecr0ss-beam and movable sheave block, the combination of means comprising a pair of gravity catches pivoted on the cross-beam a projection on the upper end of one of said catches means on the sheave block plates with which said catches engage, a weight slidably mounted on said sheave block plate adapted to engage with said projection a weighted lever pivoted on said'sheave block plate adapted to control the movements of said weight, and spring controlled means arranged to control the movements of said weighted lever according to the relative position ofthe operative parts of the grab.

4. In a grab ofthje type provided with means connecting the cross-beam and movable sheave block, the combination of means comprising a pair of gravity catches pivoted on the cross-beama projection on the upper end of one of said catches means on the sheave block plates with which said catches engage, movable means mounted on said sheave block plate adapted ,to engage with said projection, and springcontrolled means mounted on one of said sheave block latesarranged to control the movements of said movable means according tothe relative position of the operative parts of the grab.

5. In a grab of the kind herein described the combination with means for maintaining the .movable sheave block plates in correct relation with the cross-beam of means comprising a pair of gravity. .catchestpivoted on said cross-beam, means carried by said e b ockip a es ith which-sai gl gravit z;

t es

' closed position,

.one of said sheave catches engage, a locking device mounted on one of said sheave block plates adapted to engage with one of said gravity catches to maintain said part in engagementwith its co-acting part When the buckets are in means on the grab adapted to 'co-act with thetravelling carriage of a transporter means for preventing the 7 opening of the bucket sections while the grab is supported on said travelling carriage comprising a verticallydisposed gravity catch pivoted on a fixed part of the grab adapted to engage with means on the'movable sheave block plate means on the aforesaid locking device adapted to co-act with and disengage theverticall'y disposed gravity catch, and spring controlled means adapted to control the movements of said locking device according to the relative position'of the operative'parts of the grab.

6. In a grab of the the combination with means for maintaining the movable sheave block plates in correct relationwith the cross-beam of means comprising a pair of gravity catches pivoted on 'saidcross-beam, means connecting the lower ends of said'gravity' c'atchesto cause them to operate in unlson with each other means carried-by said sheave block plates with which said gravity catches engage, a bell crank lever pivoted on one of said sheave blOck plates adapted to engage with one of said gravity catches to maintain said part in engagement with its co-acting part, means o-n'the head of the grab adapted to co-act- With the travelling carriage of a transporter, a vertically disposed gravity catch pivoted on afixed part of the grab, toothed means on the movable sheave block plate with which said vertically disposed gravity catch engages, means on the aforesaid bell crank lever adapted to co-act with the vertically disposed gravity catch, and spring controlled means adapted to control the movements of said bell crank lever according to the relative position of the operative parts of the grab.

7 In a grab of the kind herein described the combination with means for maintaining themovable sheave block plates in correct relation with the cross-beam of means comprising a pair of gravity catches pivoted on said cross-beam, means connecting the lower ends of said, gravity catches to cause them to operate in'unison with each other, co-acting means carried by said sheave block plates, a locking device mounted on block plates adapted to engage with one of said gravity catches and maintain said part in engagement with 1ts co-acting part, means adapted to co-act and engage with the travelling carriage of a transporter, means for preventing the opening of the bucket sections while the grab is supported on said travelling carriage,

kind herein described means on the aforesaid locking device adapted to co-act with and throw the last named means out of operation, and spring controlled. means adapted to control the movements of said locking device according to the relative position of the a operative parts of the grab. v f

8. In a-grab of the kindhereindescribed the combination with means for'maintaining the movable sheave block platesv in correct relation with thecross-beam of means comprising a pair ofgravityicatches pivoted on said cross-beam, means connecting the lower ends of said gravity catches .to cause them tooperate in unison with each other, means carried by said sheave-block plates with which saidv gravity catches engage, a weight slidably mountedon one of sai sheave block plates adapted to engage with one of said gravity catches to maintain said part in engagement with its co-acting part, a weighted lever pivoted on said sheave block plate, adapted to control the -movemeans on the head of the travela vertically ments of said weight, the grab adapted to co-act with ling carriage of a transporter,

disposed gravity catch pivoted on a fixedpart of the grab, toothed means on the movable sheave block late with which said vertically disposed gravity 7 catch engages, means on 'the aforesaid slidable' weight adapted to' co-act with the. vertically disposed gravity catch, and spring controlled means adapted to control the movements of said weighted lever according to the relative position of the operative parts of the grab. Y

9. In a grab of the kind herein described the combination with means for maintaining the movable sheave block plates in correct relation with the cross-beam of means comprising a pair of gravity catche pivoted on said cross-beam a projection on the upperend of one of said catches, means connecting the lower ends of said gravity catches tocause them to operate in unison with each other, co-acting means carried by said sheave block plates, a locking device mounted on one of said sheave block plates adapted to engage with aforesaid projection so as to maintain the gravity catch inengagement with its co-acting part, means on the head of the grab adapted to co-act and engage with the travelling carriage of a transporter, a vertically disposed gravity catch pivoted on a fixed part of the grab, toothed means on the-movable sheave block plate with which said vertically disposed gravity catch engages, means on the aforesaid locking device adapted to engage with the vertically disposed gravity catch, and

the combination with means for maintaining the movable sheave block plates in correct relation with the cross-beam of means comprising a pair of gravity catches pivoted on said cross-beam, means connecting the lower ends of said gravity catches to cause them to operate in unison With each other, co-acting means carried by said sheave block plates. a locking device mounted on one of said sheave block plates adapted to engage With one of said gravity catches, means on the head of the grab adapted to co-act with the travelling carriage of a transporter, a

adapted to co-act With and disengage the vertically disposed gravity catch, and spring controlled means adapted to control the movements of said locking device according to the relative position of the operative parts of the grab.

DUDLEY JAMES BARNARD, 

